1. Technical Field
The invention relates to a device for the control of flowing media, in particular a vacuum valve, having closing elements, movable within a valve housing, for valve apertures and having lines adjoining the valve housing, specifically a supply line leading to a (vacuum) pump and a consumer line or suction line leading to a consumer.
2. Prior Art
Valves for flowing media, in particular compressed air or vacuum, are in many cases equipped with a rigid closing element movable within a valve housing. This is customarily spring-loaded in one direction, for example in the closing direction. As a result, opening and closing movements are sluggish, so that short cycle times are not possible in the long term.
It is an object of the invention to propose a valve which permits a simple design and actuation of closing elements and is efficient in the long term.
To achieve this object, the (vacuum) valve according to the invention is characterized in that at least one closing element is formed as an elastically deformable shaped piece, in particular as an elastic diaphragm, which can be moved into an open or a closed position by reason of elastic deformation by being subjected to the action of a pressure medium.
The diaphragm, as a closing element, is sealingly clamped along an annular circumferential edge and can be deformed by being subjected unilaterally to the action of a pressure medium, in particular of compressed air, until it comes to bear on a valve seating.
The vacuum valve according to the invention is preferably employed for the controlling of air in lifting heads with suction elements to pick up articles. The vacuum valve is particularly suitable for controlling the vacuum at individual suction heads of a suction lifter, as is illustrated for example in U.S. Pat. No. 5,666,786.
A special feature of the invention lies in the concept of piloting of the valve. The use of a pilot valve ensures that subatmospheric pressure is always active when the (two) diaphragms are switched over. Specifically, the diaphragms are each deformed into an open position by subatmospheric pressure and into the closed position by compressed air. As a result, very rapid working cycles of the valve are possible.
According to an advantageous embodiment of the vacuum valve, a flow pipe is positioned within the housing, one diaphragm being assigned as a closing element to each of its two ends. The diaphragms are supplied with compressed air from the central compressed air supply of the (packaging) machine. As a result of the actuation of one or the other diaphragm, and closing of one or the other end of the flow pipe caused thereby, a suction line leading to the lifting head or to the suction heads is connected to a supply line leading to the vacuum pump or the suction line of the suction heads is vented.